1. Field of the Invention
This invention relates generally to machine tools, and more particularly to a turning machine which simultaneously removes material from both the outer and inner cylindrical surfaces of rings.
2. Description of the Prior Art
A U.S. Pat. No. 5,293,794 issued to me on Mar. 15, 1994, some of the disclosure of which is incorporated herein directly, and the rest of which is intended to be incorporated by reference if needed, shows and describes a turning and boring machine which receives workpiece ring blanks supplied to a work station by a shuttle. It uses a linearly-driven, crescent-shaped workpiece positioner, to move a workpiece ring in one direction toward a position against the end of an idle, powered spindle while, at the same time, centering the workpiece ring on the spindle axis. Because of the centering function, the positioner is sometimes referred to as a "centering ring." The powered spindle then moves the workpiece ring, with the positioner still engaged with the workpiece ring, linearly in the opposite direction, to force the workpiece ring against a locating spindle on the same spindle axis, clamping the workpiece ring against the locating spindle. Then the centering positioner retracts to a home position, the powered spindle begins rotating the workpiece ring on the spindle axis, and turning tools are advanced to machine both the interior and exterior surfaces of the workpiece ring to finished dimensions to form a bearing race, for example. Then the powered spindle is stopped and retracted and the finished workpiece exits the work station by gravity.
The machine described in the above-mentioned patent introduced new concepts for machined ring production, for speed and efficiency. The present invention facilitates production of larger and heavier parts, individually. It also facilitates processing multiple parts simultaneously.